Regional Transported Dust To The Las Vegas Valley From Mojave and Sonoran Desert Areas CDAWG November, 2013

Transported Dust Presentation Overview Clark County PM 10 monitoring network Clark County PM 10 design values July 3, 2011 transported dust event May 10, 2012 transported dust event April 15, 2013 transported dust/high-wind event Conclusions and suggested next steps

Clark County PM Monitoring Network

Clark County Monitoring Network - Urban Core

Transported Dust Routes Into LVV

Where Is All This Dust Coming From? July 3, 2011 PM 10 Transported Dust Event – Meteorology assessment indicates desert sources south of Bullhead City, Arizona (Haboob) – Low velocity winds transported the airborne dust from Bullhead City to the Las Vegas Valley – Winds picked up in afternoon and cleared transported dust out of the Las Vegas Valley - Local wind driven sources did not contribute to the high PM concentrations

Source: Desert Meteorology. Thomas T. Warner Desert Storm “Haboob”

12hr Backward Trajectory HYSPLIT for Boulder City and J. D. Smith DAQ Monitoring Stations July 3, :00 PST

Where Is All This Dust Coming From? May 10, 2012 PM 10 Transported Dust Event – Meteorology assessment indicates northwestern Arizona Haboob/Weather event near Phoenix, Arizona pushed large desert storm dust concentrations into the Eldorado Valley (Boulder City) corridor into the Las Vegas Valley – Winds picked up in afternoon and cleared transported dust out of the Las Vegas Valley to the Northwest - No local sources of dust in Las Vegas Valley added to the mix

HYSPLIT at the Boulder City and Jean DAQ Monitoring Stations for 10 Meters Above Ground Level Note: NOAA HYSPLIT model shows two different source regions; one out of California and the other from northwestern Arizona. However, the bulk of the dust came from the northwestern Arizona desert storm (HABOOB).

Attainment Status Las Vegas Valley PM 10 Monitoring Site Average (µg/m 3 ) Site Design Value (µg/m 3 ) Paul Meyer Sunrise Acres Joe Neal Green Valley Palo Verde JD Smith Jerome Mack PM 10 Design Values *Excludes exceptional events that have been flagged Dust Transport Event (May 10, 2012) Dust Transport Event (July 3, 2011)

Where Is All This Dust Coming From? April 15, 2013 PM 10 Dust Transport/High-Wind Event – Meteorology assessment indicates dust was transported from sources in the desert east of Edwards AFB and the cities of Barstow and Baker, California and the Jean dry lake bed, in the Ivanpah Valley (Southern Nevada) – Dust followed the transportation corridor to the Las Vegas Valley; the I-15 corridor

Dust Transport/High-Wind Event (April 15, 2013) PM 10 Exceedance Concentrations for the Day: Palo Verde – 213 µg/m 3 Paul Meyer – 165 µg/m 3 Joe Neal – 227 µg/m 3 Sunrise Acres -268 µg/m 3 J.D. Smith - 238µg/m 3 Green Valley - 197µg/m 3 Jean (Ivanpah Valley) - 169µg/m 3 Boulder City (Eldorado Valley) – 246 µg/m 3

A strong pre-frontal trough moved through the Baker, and Barstow, California area on the 14 th which raised a large amount of dust. The large mass of suspended dust moved north, east and into parts of southern Nevada and northwest Arizona. The high winds over the western Mojave Desert continued to transport suspended dust into Clark County for most of the day. Additional information on April 15, 2013 Transported Dust/High-Wind Event:

Desert Dust Storm – “Haboob”

Conclusions Conditions exist that are out of our control ⁻Transport follows I-15 corridor out of the Mojave Desert and the 93/95 corridor out of the Sonoran/Mojave Desert ⁻Continued impacts from high-wind events Transported dust is major contributor to high/elevated PM concentrations in Clark County for the past 3 – 4 years and the trend is continuing Modeling analyses indicate that transported/high- wind dust events in the Las Vegas Valley do not impact other areas either to or towards the Grand Canyon (Visibility degradation) or areas immediately north-north west of the Las Vegas Valley

Suggested Next Steps Facilitate multi-state collaborative efforts to address pollutant transport issues Re-activate the Best Available Control Measure Working Group (BACM) – Provides mechanism for collaboration between air agencies in the desert southwest (AZ, CA and NV) – Group can focus on transport issues, involving Particulate Matter and Ozone, including impacts from wildfires and high-wind events

Suggested Next Steps (continued) – Share modeling data and collaborate on refining input data – Collaboratively share and analyze modeling results – Collaboratively develop approaches to reduce emissions from major sources of dust in the desert southwest – Collaborate on atmospheric field measurement studies and mutually support other agencies studies, to the extent possible

23 Questions? Russell Merle: Rodney Langston: